This application claims priority under 35 USC 119 from Japanese Patent Application No. 2002-167411, the disclosure of which is incorporated by reference herein.
1. Field of the Invention
The present invention relates to an exposure device, and in particular, to an exposure device which exposes a photosensitive material with a light beam modulated by a space modulation element or the like in accordance with image information.
2. Description of the Related Art
Conventionally, various types of exposure devices, in which exposing is carried out with a light beam modulated by using a space modulation element such as a digital micro-mirror device (DMD) or the like in accordance with image data (image information), are proposed.
For example, the DMD is a mirror device in which many mirrors whose reflecting surface angle can be changed in accordance with control signal are arranged on a semiconductor substrate such as a silicon substrate or the like in two dimensional manner. A exposure device using the DMD has a light source, a (first) lens system, the DMD and a (second) lens system. The light source irradiates a laser light. The first lens system collimates the light beam irradiated from the light source. The DMD is disposed in a substantially focusing position of the first lens system. The light beam reflected at the DMD is image-formed by the second lens system on a scanning surface. The light beam is modulated by on-off controlling of each of the micro-mirrors of the DMD by the control signal generated in accordance with the image data or the like. Image exposure is carried out by the modulated laser light.
Such exposure device is used, for example, for exposing a photo resist which is used when manufacturing a printed wiring plate. As the result, many advantages are obtained such that cost for manufacturing and managing a photomask is reduced, a time required for trial manufacturing of a printed wiring board becomes shorter, change of design or the like of a circuit can be carried out easily and speedy, and the like. Recently, a build up wiring plate has been developed in order to respond to requirement for high density packaging. Using of the above mentioned exposure device when manufacturing the build up wiring plate has been investigated.
However, when manufacturing of the build up wiring board, an electric circuit (a wiring pattern) is formed on a surface of a build up layer laminated on a core substrate by an alignment mark (an inner via, a pattern, a pad or the like) provided at the core substrate (an inner layer substrate) being as a reference. Accordingly, the exposure device has a problem in an alignment (identification of the alignment mark and positioning (aligning) of an exposure pattern) which is carried out after the build up layer is laminated on the core substrate.
For example, such as a scanning type drawing equipment described in a Japanese Patent Laid-Open No. 2000-275863, when a pattern is recorded on a laminated material of a print wiring board or the like by means of a conventional device which directly exposes (records image) on a photo resist in a mask-less manner, an alignment mark such as a through hole or the like is detected by an image-pickuping device with a visible light, and a wiring patter formed on each layer is positioned (aligned). However, it is difficult to identify the alignment mark on the core substrate after building up (laminating) of the build up layer by such image-pickuping device using a visible light when manufacturing the build up wiring board. Therefore, establishment of alignment technology becomes a problem in a case of to using an exposure device which exposes a pattern (an image) with light beam when manufacturing the build up wiring board.
On the other hand, by that an alignment mark is masked by a tape before plating and the tape is stripped (removed) after plating thereby the alignment mark can be visually identified in order to enable to identify the alignment mark, identification may be carried out by using the image-pickuping device mentioned above or the like. However, manufacturing processes cannot be automated by the method mentioned above, merit to introduce the device fades, and there is a problem that a manufacture cost has risen.
The present invention was developed in consideration of the above mentioned problems, and an object of the present invention is to provide an exposure device by which aligning of an exposure pattern is realized when manufacturing a build-up structure such as a build up wiring board or the like, and which can cope with automation of manufacturing process.
A first aspect of the present invention is an exposure device which exposes a photosensitive material with a light beam modulated in accordance with image information, the device comprising a reading section which reads a radioscopic image of a specific pattern provided on an inner layer of a laminated structure; and an aligning section which aligns an exposure position of the photosensitive material laminated on a surface of an outer layer of the laminated structure, on the basis of position information of the read radioscopic image of the specific pattern.
In a second aspect of the present invention is the image recording device according to the first aspect, the device further comprises a spatial modulating element which modulates the light beam, and a moving section which relatively moves the spatial modulating element and the laminated structure in a direction parallel to a surface, of the photosensitive material, to be exposed, wherein the aligning section includes the moving section.
In a third aspect of the present invention is the image recording device according to the first aspect, the device further comprises a spatial modulating element which modulates the light beam, and a control section which controls the spatial modulating element according to a control signal generated in accordance with the image information, wherein the aligning section includes the control section.
In each of a fourth, a fifth and sixth aspects of the present invention is the image recording device according to the first, the second and the third aspects, respectively, the reading section is an X-ray image-pickup section which picks up a radioscopic image using an X-ray irradiated on the laminated structure.
In each of a seventh, an eighth and a ninth aspects of the present invention is the image recording device according to the first, the second and the third aspects, respectively, the laminated structure is a build-up wiring board comprising a core substrate as the inner layer and at least one build-up layer as the outer layer.
In a tenth aspect of the present invention is the image recording device according to the first aspect, the device further comprises a spatial modulating element which modulates the light beam, a moving section which relatively moves the spatial modulating element and the laminated structure in a direction parallel to a surface, of the photosensitive material, to be exposed of the photosensitive material, and a control section which controls the spatial modulating element according to a control signal generated in accordance with the image information, wherein the aligning section includes the moving section and the control section.
In an eleventh aspect of the present invention is the image recording device according to the tenth aspect, the moving section aligns the exposure position of the photosensitive material in at least one direction selected from among a main scanning direction, a sub scanning direction and a rotation direction, and the control section aligns the exposure position of the photosensitive material in the remaining direction among the main scanning direction, the sub scanning direction and the rotation direction.
In a twelfth aspect of the present invention is the image recording device according to the eleventh aspect, the reading section is an invisible light image-pickup section which picks up a radioscopic image using an invisible light irradiated on the laminated structure.
In a thirteenth aspect of the present invention is the image recording device according to the twelfth aspect, the invisible light is radiation which can transmit through the laminated structure.
In the first aspect of the present invention, the reading section reads the radioscopic image of the specific pattern provided on the inner layer of the laminated structure. The aligning section carries out an exposure alignment of the photosensitive material laminated on the surface of the outer layer of the laminated structure on the basis of the position information of the read radioscopic image of the specific pattern. That is, a position (an image recorded position) at which the photosensitive material is exposed with the light beam modulated in accordance with the image information is aligned to a predetermined position which is determined by the specific pattern being as the reference. The radioscopic image of the specific pattern is obtained, for example, by irradiating a light of wavelength which transmits through the laminated structure and the specific pattern.
As the result, in the present invention, when manufacturing of the laminated structure such as the build-up wiring board or the like, the alignment of the exposure pattern, that is, the exposure-alignment of the circuit pattern formed on the surface of the build up layer (the outer layer) can be realized by the alignment mark (the specific pattern) provided on the core substrate (the inner layer) being as reference. Further, it can be carried out to correspond to the automization of the manufacture process.
In the second aspect of the present invention, the alignment is carried out such that the spatial modulating element which modulates the light beam and the laminated structure are relatively moved by the moving section in the direction so as to be parallel to the surface to be exposed of the photosensitive material. The direction so as to be parallel to the surface to be exposed of the photosensitive material is a direction, for example, a main scanning direction of the light beam (a X direction), a sub scanning direction of the light beam (a Y direction), a rotation direction to which this X-Y coordinate system is rotated, and the like. Namely, the direction parallel to the surface to be exposed of the photosensitive material is one of the directions mentioned above, or combination of a plurality of directions mentioned above. The alignment of the exposure position can be easily realized due to that the an mechanically structured moving section is used as the aligning section mentioned above.
In the third aspect of the present invention, the control section controls the spatial modulating element to change modulating timing or the like of the light beam on the basis of the control signal generated in accordance with the image information. As the result, exposure alignment is carried out. Even if the aligning section is structured by the electrical control section which changes the modulating timing or the like of the light beam, the exposure pattern alignment can be carried out. Further, the device structure can be more simple compared to a case in which the an mechanically structured moving section is used as the aligning section.
In the fourth aspect of the present invention, the X-ray is irradiated on the laminated structure, and the X-ray image-pickup section picks up the radioscopic image (the X-ray transmitted through the laminated structure). As the result, the radioscopic image of the specific pattern can be image-picked surely. Further, the above mentioned reading section can be realized by a practical structure which is taken the image-pickuping accuracy, the cost and the like into consideration.